In the sector of tile-laying for covering surfaces, such as floorings, walls and the like, the use of spacer devices is known which, as well as spacing the tiles, enable planar arrangement thereof, i.e. are such as to lay the in-view surface of the tiles substantially coplanar; these devices are commonly known as leveling spacer devices.
Spacer devices of known type generally comprise a base, positionable below the laying surface of at least two (three or four) adjacent tiles, from which emerges at least a separator element, able to contact, by action of the lateral flanks thereof, the facing flanks of the two (three or four) tiles to be arranged side-by-side on the laying surface, defining the breadth of the space interposed between the tiles.
The leveling spacer device is also provided with presser means cooperating with an emerging portion of the separator element which emerges above the plane defined by the in-view surface of the tiles. The presser means are essentially provided with a planar surface facing towards the base which is able to press the in-view surfaces of all the products supported by the base towards the base itself so as to level the in view surfaces.
Among the leveling spacer devices of known type there exist various types, of which one has the presser element shaped substantially as a wedge which runs on the in-view surface of the products, a further type of the leveling spacer devices is known as a screw leveling spacer device and includes the presser element being essentially constituted by a knob provided with a nut screw which can be screwed to a threaded shank (or the like) associated to the emerging portion of the separator element.
Once the presser element has been screwed on the threaded shank and has performed its task of leveling the tiles, and having waited for the adhesive on which the laying surfaces to solidify, it is sufficient to separate—for example thanks to lines of pre-weakened fractures appropriately realised between the separator element and the base—the separator element from the base, which base will remain invisibly incorporated in the adhesive below the laying surface of the tiles.
The screw leveling spacer devices, with respect to the wedge devices, have the drawback that the threaded knob remains engaged with the threaded shank following the separation of the separator element from the base and in order to re-utilise the presser element with a new separator element the operatives laying the tiles must proceed to unscrewing the threaded shanks from the relative threaded knobs with undoubted drawbacks in terms of time and costs for the operatives laying the tiles.
Further, with the aim of enabling a fine regulation of the pressure exerted by the knob on the in-view surface of the tiles, the pitch of the thread of the nut screw and the threaded shank must be sufficiently modest and the threaded shank sufficiently long.
This circumstance primarily involves the need to activate the screwing of the knob for a prolonged period of time and for a large number of revolutions from the moment of engaging the nut screw with the free end of the threaded shank up to reaching the point of contact between the knob and the laying surface of the tiles, especially if the tiles are of modest thickness.
Further, the same cost for the personnel is incurred when the knob is to be reset, as described above, for unscrewing the threaded shank from the knob, and the market offers use of an insert for electric screwdrivers suitable for gripping the stump of the threaded shank which projects from the knob with the intention of accelerating the unscrewing operations.
Further, the screw leveling spacer devices, with respect to the wedge spacers, can have the drawback that the torque force exerted by the knob on the threaded shank, especially in the final stages of blocking, can unload on the separator element which—being a slim sheet, the thickness of which must be as small as possible for containing the dimension of the gap between the tiles—is often subject to torque deformations which lead to an irregular localised widening of the gap between the tiles, in fact making the spacing function of the device ineffective.
Further, the screw leveling spacer devices can have the drawback that the rubbing exerted by the knob on the in-view surface of the tiles during the final tightening steps can unload in the form of a centrifugal force on the tiles which are, therefore, distanced irregularly at the device, widening or deforming the gap between the tiles, in fact making the spacing function of the device ineffective.
To obviate this drawback use of a collar is known, insertable on the threaded shank of the device during the laying (i.e. with the base already placed below the tiles) and resting on the in-view surface of the tiles, which collar can be interposed between the laying surface of the tiles and the knob, so that the knob drags, in the final blocking stages of the knob, on the collar and the collar remains solidly in contact with the in-view surface of the tiles.
The collar, however, involves a dead time for insertion on the leveling spacer devices and an added cost for the personnel involved in the laying, who sometimes do not use it for this reason.
An aim of the present invention is to obviate the above-mentioned drawbacks of the prior art, with a solution that is simple, rational and relatively inexpensive.
The aims are attained by the characteristics of the invention as reported in the independent claim. The dependent claims delineate preferred and/or particularly advantageous aspects of the invention.